Monday, October 28, 2013

Large flocks of waders on mudflats are an impressive spectacle
but are often at long range.

Viewing birds or ships
out to sea or across mudflats and wide river mouths requires good
magnification and a reasonably bright image. In general the high
magnifications offered by spotting scopes are more useful for seeing
detail at long range, but binoculars are still very useful for
scanning across large areas and being easily portable.

Whilst high
magnification is useful at longer range the usual problems of holding
powerful binoculars steady and the restricted field of view come into
play. The highest practical magnification for most people is 12x. A
good specification to look for in this power is a 12x50, the 50mm
lenses letting lots of light which is essential for use in lower light. A more general purpose model would
be a 10x42, being lighter in weight and having a wider field of view.

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The Hawke Naturtrek 12x50

If you are able to do
most of your viewing seated or from somewhere you can rest
your elbows then a higher magnification can be used (e.g. 15x56 or
20x60 etc.) but these will be relatively heavy and bulky. Tripod mounts are available for most types of binocular that can make these higher magnifications more practical.

Scopes take over where
binoculars leave off, zoom eyepieces typically starting at 15x or 20x
and giving up to 50x-70x depending on manufacturer. The highest
practical magnification is
60x-70x, and depending on the conditions, even this can be too much. If
there is a heat haze, fog or heavy rain it doesn’t matter how good
the quality of the optics is, the weather you are looking through
will be the limiting factor. However, in clear, still conditions a
top quality scope can be a real treat at high power, even in low
light. The best results can be obtained from scopes with larger objective lenses (77-95mm).

There are many larger
scopes available both new and second hand right across the price
range that can zoom up to 60x or more, from the Acuter 20-60x80 at under £200 to
the Swarovski ATX 95 at £3000.

As good as it gets.
The Swarovski ATX 95mm has an impressively wide field across the zoom range of 30-70x